BACKGROUND: Orientin is a flavone isolated from medicinal plants used in traditional Chinese medicine (TCM), which suppresses the growth of cancer cells in vitro. The effects of orientin in bladder cancer cells remains unknown. This study aimed to investigate the effect of orientin on proliferation and apoptosis of T24 human transitional cell bladder carcinoma cells in vitro in the presence of an agonist and an inhibitor of nuclear factor-kappaB (NF-κB).

MATERIAL AND METHODS: T24 cells were cultured and divided into four study groups: an untreated control group; a group treated with 100 μM orientin; a group treated with 100 μM orientin with NF-κB agonist, phorbol 12-myristate 13-acetate (PMA); and a group treated with 100 μM orientin and the NF-κB inhibitor, IκBα. The MTT assay was performed to assess cell viability, and flow cytometry evaluated the cell cycle. The expression of proteins in the Hedgehog signaling pathway and inflammatory cytokines were determined by Western blot and enzyme-linked immunosorbent assay (ELISA).

RESULTS: Orientin inhibited the proliferation of T24 cells, caused cell cycle arrest, reduced cell viability, and inhibited the expression of inflammatory mediators. Treatment of T24 cells with orientin inhibited the expression of NF-κB and components of the Hedgehog signaling pathway, and the NF-κB agonist, PMA, reversed these effects.

CONCLUSIONS: Treatment of T24 human bladder carcinoma cells in vitro with orientin inhibited cell proliferation and promoted cell apoptosis by suppressing the Hedgehog signaling pathway and NF-κB.

Keywords: Cell Cycle, Cell Cycle Checkpoints, Glucosides, Hedgehog Proteins, I-kappa B Proteins